The invention pertains generally to ordnance disposal and in particular to pyrotechnic torches for burning out dudded munitions.
Often dudded munitions cannot be safely disposed of by detonation. Burning out the munition offers a nonviolent technique for disposing these munitions on site. Since munitions are often one-half inch thick steel enclosures of up to two thousand pounds of a heat-sensitive, gas-generating, energetic material, gaining access through the steel casing without detonating the explosive or solid propellant is extremely difficult.
Conventional metal-cutting torches are difficult to operate remotely, often do not cut quickly enough if the metal casing is steel to prevent cook off and detonation, and are expensive. They are particularly difficult to operate remotely under water.
Torches utilizing thermite powder (a mixture of a metal and a metal oxide) are unreliable because the powder or the molten metals often plug the exhaust or cutting ports of the torches. Further, these torches are very unreliable under water, sometimes detonating, and degrade upon exposure to moisture, causing unreliable performance.
The most successful torches, to date, utilize a pyrotechnic composition disclosed in Helms et al., U.S. Pat. No. 3,695,951, which comprises nickel, aluminum, ferric oxide, and powdered tetrafluoroethylene. The problems with these torches are the expense of nickel, the inability to solvent-process the composition, a high firing shock due to the generation of a high thrust immediately after achieving maximum pressure, sensitivity to moisture, and some reproducibility difficulties.
Numerous other energetic compositions are known, but are not suitable in metal-cutting torches for ordinance disposal because their thrust is too high, their heat generation is too slow, or their shelf life is too short. They are, however, useful for many other applications. The following are examples of energetic compositions and some of their uses.
A metal in a halogenated hydrocarbon binder has been used as a flare and in an electric match. The flare composition of Edgar Cadwallader, U.S. Pat. No. 3,152,935, comprises aluminum and trifluorochloroethylene. In Haas et al., U.S. Pat. No. 4,152,988, the igniter composition in an electric match comprises magnesium, two types of polytetrafluoroethylene, and a fluorocarbon rubber.
An energetic compositions comprising a metal, a metal oxide, and an organic binder have many uses. In Arthur Dierolf, U.S. Pat. No. 3,671,341, an energetic composition consisting of uranium, mercuric oxide, Viton A, and teflon is used in rocket propellant. The rocket-propellant composition of Paul Allen, U.S. Pat. No. 3,309,249 consists of aluminum, ferric oxide, and a non-halogenated binder.
Other energetic compositions have a mixture of a metal and an oxidizing salt in a halogenerated hydrocarbons. The igniter composition of Julian et al., U.S. Pat. No. 3,753,811, consists of aluminum, an oxidizing salt, a fluoride salt, polytetrafluoroethylene, and polytrifluorochloro-ethylene. Burnside, U.S. Pat. No. 3,513,043, discloses a propellant composition comprising aluminum, oxidizing salt, polyfluoroethylene resin, Viton A, and other minor ingredients.